Objective: To investigate an effectiveness of walking exercise program applying the Theory of Planned Behavior in people at risk of hypertension in Samut Sakorn province.
Material and Method: The present study is a quasi-experimental research. The inclusion criteria were people aged 35-59 years old, systolic blood pressure 120-139 mmHg, and diastolic blood pressure 80-89 mmHg. Participants were randomly selected into the experimental group (n = 34) and the comparison group (n = 34). The experimental group received activities including health information, benefits of walking exercise, group discussion in exercise barriers, modeling and experience exchange, walking exercise practice, and practice on using walking monitoring booklet at the baseline and the 2nd week, whereas the comparison group received only health information and the booklet practice at the beginning of the intervention. Data were collected by self-administered questionnaires at the baseline, 2nd week, and 6th week. Statistical analysis was performed using Chi-square, Independent t-test, and repeated measures ANOVA.
Results: The experimental group made significant improvements in attitude towards walking exercise, perceived behavior control, subjective norm, walking exercise intention, and walking exercise over time (p<0.05). However, no statistically significant differences between the experimental and the comparison groups were found in subjective norm, systolic and diastolic blood pressure from baseline to the 6th week. The experimental group had a significant higher mean difference score of attitude towards walking exercise, perceived behavior control, walking exercise intention, walking exercise, weight, and BMI compared to those in the comparison group (p<0.05). Subjective norm scores in the experimental group were more likely to increase from baseline to the 6th week, but not a significant difference.
Conclusion: Walking exercise programs applying the Theory of Planned Behavior should be recommended in people at risk of hypertension. Health professionals should also be motivated to practice with this program.

Keywords: Walking exercise, Hypertension, Theory of planned behavior, Risk population